The disclosure relates to a glass ceramic article, such as a cover plate for consumer electronic devices. More particularly, the disclosure relates to a method of making such glass ceramic articles. Even more particularly, the disclosure relates to a method of making such articles using frit material comprising such glass ceramics.
Shaped glass ceramic articles are entering use as outer cover or enclosure elements in consumer electronics such as mobile phones and tablets. Currently, these articles are made by first forming a “green” or unfired sheet, crystallizing (“ceramming”) a portion of the sheet to form the glass ceramic, reforming the glass ceramic to its final or near net shape, and, if necessary, machining the article to its final form.
Machining complex glass ceramic shapes suffers from the disadvantage that it introduces flaws that reduce the overall strength of the glass ceramic article. In addition, tolerances for some applications are tight, typically in the range of ±100 microns (μm). Meeting such tolerances is challenging due to volume changes that occur during the ceramming process. Moreover, since ceramming is performed at a temperature that is greater than the softening point of the green glass ceramic, three dimensional shapes may distort unless they are held in a precision mold.